(ProPublica) – Decades ago, Kris Hansen showed 3M that its PFAS chemicals were in people’s bodies. Her bosses halted her work. As the EPA now forces the removal of the chemicals from drinking water, she wrestles with the secrets that 3M kept from her and the world.

As the lab equipment hummed around her, Hansen loaded a sample into the machine. A graph appeared on the mass spectrometer’s display; it suggested that there was a compound in the blood that could be PFOS. That’s weird, Hansen thought. Why would a chemical produced by 3M show up in people who had never worked for the company? (Read More)